Thread:CelestialCheese/@comment-33327767-20171018120938/@comment-26120508-20171019205402

Porygon evolves into Porygon2 by trading while holding an Up-Grade (Up-Grade costs 150 BP at Battle Colosseum)

Porygon2 evolves into Porygon-Z by trading while holding a Dubious Disc (Dubious Disc is found in Anthian Sewer)